photos by MICHAEL PATRICK/NEWS SENTINEL
UT Culinary Institute and UT Extension Service partnered to teach a Canning College class Monday. Heather Kyle, right, demonstrates filling the jars during this session on how to properly can green beans using a pressure canner.$RETURN$$RETURN$

If you are familiar with the rocking motion of a plastic hula girl on a car's dashboard, you're already ahead of the game when it comes to pressure canning.

That and more was revealed Monday evening at the 2013 Principles of Home Canning class given by Heather Kyle and Chris Sneed, Extension agents for the University of Tennessee Institute of Agriculture.

While students snapped green beans in preparation for the kitchen portion of the class, a slideshow on pressure canning was presented.

Sneed said most vegetables and all meat products are considered low acid foods that must be processed in a pressure canner to prevent the possibility of botulism.

"What we are doing (when putting a low acid vegetable in a jar with water) is creating a honeymoon suite to grow and reproduce clostridium botulinum." In laymen's terms that's botulism.

The only way to prevent that growth is to process the product at a temperature above the boiling point of 212 degrees. A pressure canner can get the interior temperature of a pressure canner up to 240 to 250 degrees, which will kill the deadly toxins.

Whether a food is low acid or high acid is determined by its pH value. A handout sheet was included in a booklet given to students that provides the pH value of a variety of foods.

However, Sneed said the best way to determine how a product should be canned is to follow the directions using tested recipes from a legitimate source.

"The pH scale gets blurry when you get in the middle range, especially with tomatoes and figs, which fall right on the dividing line," he said.

Tested recipes from sources such as the National Center for Home Preservation, UT Extension Service and/or the Ball Blue Book take the guesswork out of the equation by providing the proper processing recommendations.

"Tomatoes, in many cases, have the option of being prepared in a pressure canner or in a water bath canner, except for something like stewed tomatoes that have green peppers and onions added to them. That, of course, changes the pH and would become a pressure canned product," he said.

There are three types of pressure canners: a weighted canner, a gauge canner and the "Cadillac" of canners that includes both weight and gauge.

Kyle displayed each type, showing that the gauge features a numbered dial which displays the amount of pressure being produced inside the canner, while the weights move in a swaying motion (hence the hula girl comparison), which lets you know that the pot is working properly.

"The rocking sound is what you want to go on. It's a bit ambiguous at first but you learn what you are looking for. You don't want it to be too fast, and you don't want it to be too slow," Kyle said,"

If using a gauged canner, the gauge should be tested yearly to make sure it's properly calibrated. The UT Extension Service provides that service.

Kyle said all of the canners will get the job done; it's just personal preference whether you want a gauged, weighed or combo canner.

Students' hands-on training began with sterilizing their jars and lids and placing the jars in a warming oven until ready to fill.

The green beans were washed and placed on the stove, covered with water and brought to a rolling boil. After 10 minutes they were removed from the stove, ladled into warm jars, with Kyle showing the class how to extract air bubbles from the jars by inserting a straight object (plastic recommended) between the interior side of the jar and the vegetable, pressing inward to release any excess oxygen. Proper head space was measured before the lids were placed on the jars.

Then jars were placed in a canner that had 2-3 inches of hot water in the bottom. The class was shown how to line up the arrows featured on both lid and pot so that the canner would close properly.

"Now throw the heat to it," Sneed said, as the class turned up the gas eyes on the industrial stoves, waiting for steam to be released from the canner valve. After a steady pace of steam was released for 10 minutes the vent port was covered and pressure began to build.

When the weighted canner began to rock too fast, the stove temperature was lowered. The same was done when the gauge surpassed the 11 pounds of pressure recommended for the recipe.

Following 20 minutes of cooking time, the canners were removed from the stove and left to depressurize for approximately 10 minutes. When the cookers were unsealed and the cans were removed, students saw that the water inside each jar was still at boiling stage. As they cooled, the satisfying pings of sealing jars were heard throughout the room.

Kyle said pressure canning has received a bad rap over the years but it's really not a dangerous procedure as long as attention is paid to the process.

"Most accidents have happened because people were not being as cautious as they should be," she said.

Sneed added that in 1978 a locking bracket was added to pressure canners which prevents them from blowing up or being opened before they have depressurized.

Cyndi Cunningham of Montverde, Fla., came to the class with her sister Teri Roy of Knoxville. Both have fond memories of being in the kitchen with their grandmother when she would can, and they thought they needed a refresher course.

"I really believe in diversified food preservation. There's a real need for this in our community, and I get great satisfaction knowing where my food came from and how it was processed," Roy said.

4 Place jar rack and 2-3 inches of water in pressure caner. Add sealed jars. Fasten canner lid and heat on high setting. After exhausting steam for 10 minutes, add weighted gauge or close petcock to pressurize the canner.

5 Process at 11 pounds pressure if using dial gauge pressure canner or at 10 pounds pressure if using weighted gauge pressure canner. Pint jars should be processed for 20 minutes. Quart jars should be processed for 25 minutes.

Note: An average of 14 pounds of beans is needed per canner load for 7 quarts or 9 pounds of beans for 9 pints. A bushel weighs 30 pounds and yields approximately 12-20 quarts.